Welcome to Neptune

Neptune is often seen as Uranus' twin planet. It is similar in size and colour, and has a similar chemical make-up. It was discovered in 1846 by Johann Gotfried Galle when scientists realised that it was difficult to predict
Uranus' orbit. It became obvious that there must be something further away in space pulling on
Uranus. This object turned out to be Neptune.

The giant blue planet, slightly smaller than
Uranus at 49,500 kilometres wide (Uranus is 52,000 kilometres wide) takes 165 years to orbit the
Sun, meaning that it never completes a complete journey around the Sun during the lifetime of anybody on
Earth, and since its discovery, it has only orbited the
Sun once. The completion of its first orbit was as recent
as July 2011. It may surprise you to know that Earth, is the next biggest planet in the Solar System,
but it could fit into Neptune 60 times!

Voyager 2, a space craft designed to visit the four
Gas Giants (Jupiter,
Saturn, Uranus and Neptune) arrived at
Uranus in 1986, and revealed a bland, boring world. Scientists
half-expected Neptune to be similar. However, pictures from
Voyager, when it arrived at Neptune on 24th August 1989, (12 years after the
Voyager probes were launched) showed Neptune to be a deep blue-coloured planet with white, whispy clouds in its atmosphere, the strongest winds in the Solar System, and a dark spot, similar to
Jupiter's Great Red Spot, which was the size of
Earth. Incomplete rings, looking like arcs, orbited the planet, suggesting that they haven't had time to completely form yet, and one of
Neptune's moons (Triton) showed that, with its eruptions of nitrogen gas, even at the furthest reaches of the Solar System, geological activity still takes place.

Neptune, like Jupiter,
Saturn and Uranus, has a thick gassy atmosphere full of mainly hydrogen and helium. Below this are huge amounts of
frozen material, possibly water and liquid ammonia. The planet also contains Methane which gives the planet a blue colour, like
Uranus. Winds on Neptune can blow at speeds up to 2,000 kilometres an hour!

Surrounding Neptune are thirteen known moons. These moons are all very small, apart from
Triton, an active moon. Between the years 1930 and
2006, Neptune was the eighth of nine planets in the Solar System. During this
time, Pluto was the ninth planet and most
distant. In 2006, astronomers decided to classify
Pluto as a Dwarf Planet and Neptune regained its
status as the Solar System's most distant planet, and therefore the last of the
planets. Even while Pluto was a regarded as a
planet, there were times when it came closer to the Sun than Neptune and
temporarily made Neptune the most distant.